Jeffrey K. Reneau, Professor, Dairy Management

March 11, 2006

Beginning in June of 2003 Minnesota dairy producers began a concerted effort to improve milk quality. This industry-wide Quality Count$ campaign had a profound effect. Minnesota dairy producers succeeded for 24 consecutive months in decreasing the average monthly somatic cell count (SCC). But since June 2005, that trend has reversed as can be seen in the Minnesota DHI SCC graph below. Fueled by the relatively warm and wet weather last summer, fall and even this winter, Minnesota SCC levels are on the rise. It's time for us to do some spring cleaning to get the bulk tank somatic cell count (BTSCC) back on track.

What can you do?

• Identify the high SCC quarters. Use a DHI SCC list or a California Mastitis Test paddle to identify those high SCC quarters. Then use a quarter milker on those high SCC quarters (of cows not being treated with antibiotics) to keep the high shedding SCC quarter milk out of the bulk tank. With this strategy, you can win the milk quality battle practically over night. But unless you take further steps to reduce the cause(s) of the mastitis infection, you will continue to lose the mastitis war. However, this is a good short term approach and perhaps a place to begin while you are focusing on a more comprehensive problem solving effort to reduce herd mastitis.


• Find the causes. If you really want to make sustained progress in both improving milk quality and reducing mastitis, then you must search and eliminate the root causes of the problem(s). Since every farm is different, neither the causes nor solutions will be exactly the same. Seek help from your veterinarian and milk plant field rep to do a detailed diagnosis of your herd mastitis problem. Study your herd records (DHI and on-farm records) to determine which cows are affected, when during lactation infections occur, and the seriousness of the problem. Do a bulk tank culture to uncover what bacteria are the most likely culprits. Once this information is gathered, you will be able to formulate a specific plan that will work for your herd. See the Dairy Extension website www.extension.umn.edu/dairy and click on "Quality Count$" for fact sheets providing detailed instruction on taking bulk tank milk samples as well as interpretation of culture results.


• Bedding management and cow prep. In the past 25 years, almost without exception, I have seen that a reduction in herd SCC can be achieved by improving the quality of pre-milking cow prep and bedding management. Improving bedding management reduces teat exposure to mastitis pathogens. Improving cow prep reduces chances of new infections occurring during milking. If a concerted effort in these two areas were made statewide in Minnesota, we would see a dramatic reduction in BTSCC. In most cases, it is as simple as keeping teats clean.


• Use the teat swab test. The correlation between teat cleanliness and SCC is convincingly shown by a French study. Using the teat swab test found with the other Quality Count$ materials on the above mentioned University of Minnesota Dairy Extension website, you can assess your own pre-milking teat cleanliness.




• Cow hygiene score card. A University of Minnesota study showed that in herds where environmental mastitis predominate, hygiene of the lower rear legs and udder correlated to SCC. Cows with higher cow hygiene score also had a higher SCC. The average hygiene score for rear legs and udders for cows in this study was 2.95 (on a hygiene score scale of 1-5 with 1 being spotlessly clean and 5 being very dirty) and the average SCC for the 1191 cows studied was 405,000. For the cows in this study, every 1 unit score improvement in hygiene resulted in a 50,000 reduction in SCC. Using the cow hygiene score card, also found on the above mentioned website, you can determine the potential SCC impact of keeping your cows cleaner.

Cows are dirtier in early lactation. Unfortunately this is also the time when they are most vulnerable to getting new mastitis infections because their immune system may be somewhat depressed. Therefore, more intense bedding and stall management should be given to maintain clean and dry stalls for close-up dry cows, fresh and early lactation cows.

University of Minnesota Diagnostic Lab culture records indicate that most of the mastitis in Minnesota dairies is coming from environmental pathogens. That is why the bottom line for reducing Minnesota BTSCCs boils down to hygiene. More effort in keeping cows cleaner and more effort in cleaning teat surfaces prior to milking will always pay off in lowering BTSCC. How about it? Let's all initiate a "spring cleaning" in a concerted effort to get Minnesota's SCC back on track.